MTFCA Forum

In researching Holley G float adjustment I came across these diagrams. I wonder if anybody here can ID the source publication.

Steve,

It's from the January 1st, 1920 Ford Service Bulletin

Hi Steve,
I was wondering if you are looking for the carb tools shown in the illustrations? I don't have them but If anyone has a pattern to reproduce carb tools it would be most likely of great interest. It is not my intention to tread on your thread but just saw your trip post and you had what I am going to assume poor gas mileage and the carb has become a point of interest.

There is a third diagram that goes with those two. It's a drawing of using the low speed tube clearance gauge 24-Z2390

...you had what I am going to assume poor gas mileage and the carb has become a point of interest.

Not only poor mileage, but difficult starting. I took off the top plate to have a look at the fuel level and it looked like a lake in there. So now I'm working on the equipment for proper float setting on a G, including the temporary fuel source. If Murray Fahnestock's ½" setting was ever valid, I think the modern float makes it bogus, so I want to set the level by the recommended method. I may just switch to an NH until I can do that.

Steve

Most of that Jan 1920 Service Bulletin, on MTFCI hompage historical document tab.

http://www.cimorelli.com/mtdl/service_b ... sb1920.pdf

Steve, the fuel.level should not change with a different float. The dry level setting will change due to differences in buoyancy of the different floats, but the fuel level spec will remain the same. Example, if the float is heavier it will ride lower in the fuel giving a higher fuel.level for the same dry setting. If it was suppose to be 1/2 inch of fuel in the well, it will still be 1/2 inch. Hope this made sense.

Andy

Hi Steve

If you are up to it, you can also check and adjust the fuel level with the carb on the car, but it does involve crawling under to remove the bowl and float when an adjustment is needed.

Also, I the correct fuel level is much less than 1/2 in and is measured in the bottom well of the fuel jet seat. If the level is a bit too high, it will dribble out the bottom through the high level overflow tube. This tube sticks about 1/16th inch above the base of the inside of the carb body. If it gets beat or ground down the carb won't run right and may leak more.

The 1/2 inch reference is more likely the starting measurement for the distance from the flow to the body flange when it is held upside down like when the NH is checked. However this is only a starting point, the level must be set per the specification as the level in the jet bowl.
Once the engine starts, the puddles is sucked away and the jet takes over to control the spray of the fuel. The jet opening often also has opened up over time and may need be resized.

I would also recommend getting the carb rebuild guideline produced by the MTFCA. It covers the Holley G in much better detail that I can describe here. It also includes some diagrams on making the tools needed to service the carburetor.

Some previous researching on the MTFCA forum recommended the Holley G as one of the better carbs for use on the non-starter cars (it was original equipment). It also tested much better than the Kingston that was also used at the time.

It took me a while, but using the book as a guideline I rebuild my bronze body Holley G and it works well on the my '15T. And I think my mileage is better than 15, but I haven't measured it in detail yet.

Drive Safe
Jeff

Watching this closely as I have the same diagrams along with Mart's drawings but no idea where I found the diagrams...

...you can also check and adjust the fuel level with the carb on the car...

In my roadside session in Missouri I did take off the cover for a look-see with the carb in the car, but I didn't want to mess with the engine pan, so I took it out to adjust. Fahnestock's half inch refers to the distance from the flange to the top of the float, just like the ¹⁵⁄₆₄" when you set the NH float. I aim to adjust this G according to the MTFCA book, so that's on hold while I devise the little temporary fuel supply. Meanwhile the NH is back on the car so I can drive it.

Royce Peterson has been posting some detailed carburetor rebuilding articles on his Model T Ford Fix site. The February 25, 2018 post has very detailed info on the Holley Model G, and its adjustment after rebuilding.